Urine nitrification and sewer discharge to realize in-sewer denitrification to simplify sewage treatment in Hong Kong

F. Jiang, Y. Chen, Hamish Mackey, G. H. Chen, M. C M Van Loosdrecht

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15 Citations (Scopus)


The chemically enhanced primary treatment works in Hong Kong will be upgraded for biological nitrogen removal. This study proposed a novel approach to waive the upgrading by urine sourceseparation, onsite nitrification and discharge of nitrified urine into sewers to achieve in-sewer denitrification. Human urine was collected and a lab-scale experiment for full urine nitrification was conducted. The results showed that full nitrification was achieved with alkaline addition. Simulation of nitrified urine discharge into an 8-km pressure main in Hong Kong was conducted with a quasi-2D dynamic sewer model developed from a previously calibrated sewer biofilm model. It was assumed that 70% of the residents' urine was collected and fully nitrified on-site. The simulation results revealed that the proposed approach is effective in removal of nitrogen within the sewer, which decreases ammonia-N at the sewer outlet to a level required for secondary effluent discharge in Hong Kong.

Original languageEnglish
Pages (from-to)618-626
Number of pages9
JournalWater Science and Technology
Issue number3
Publication statusPublished - 2011
Externally publishedYes



  • Denitrification
  • Human urine
  • Nitrification
  • Sewer modeling

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology

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